Rodrigo Duterte, Philippine presidential candidate and a local mayor raises his fist during a motorcade campaign at Cainta Rizal, east of Manila April 12, 2016.

Philippine presidential election front-runner Rodrigo Duterte, who made widely condemned remarks about the rape and murder of an Australian missionary, warned he will cut diplomatic ties with the US and Australia.

The ambassadors of Australia and the US criticised Duterte for saying he should have been the first to rape the 'beautiful' missionary. The presidential favourite, who retained the top spot in the latest opinion survey, reacted by asking the ambassadors to shut their mouths.

"If I become president, go ahead and sever it (diplomatic ties)," Duterte said in a campaign speech on Wednesday, the Agence France-Presse reported. Australia and the US are two of closest allies of the Philippines.

"They raped all of the women... there was this Australian lay minister... when they took them out... I saw her face and I thought, 'Son of a bitch. What a pity... they raped her, they all lined up. I was mad she was raped but she was so beautiful. I thought, the mayor should have been first," Duterte told during the campaign.

"I apologize to the Filipino people for my recent remarks in a rally. There was no intention of disrespecting our women and those who have been victims of this horrible crime. Sometimes my mouth can get the better of me," he said.